A number of industries, such as the mining industry, rely on large off-highway trucks to transport large cargo loads. Not only are the loads themselves extensive, but these trucks are frequently operated around the clock. Manufacturers or dealers of these off-highway trucks typically provide a warranty for the truck, often covering the entire life of the vehicle. Because this type of warranty may be costly to the manufacturer, the manufacturer often specifies operating and maintenance standards, such as maximum operating weights, in order to achieve a longer operating life of the vehicle.
Sometimes the specified maximum operating weight is viewed as the target weight, rather than a weight that should not be exceeded, as there may be divergent interests in this area. Hauling a heavier load may result in a greater profit for the operation, at least in the short term. But, frequent overloading will adversely affect equipment life and operation. Overloading may also result in reduced fuel efficiency and increased operating costs. Additionally, overloading may increase wear on components and may break structural joints. Some studies have shown that every one ton increase in mean payload (or cargo weight) above target decreases component life by approximately 1%. Further, repeated overloads may potentially decertify brake and/or steering systems in the equipment.
As noted above, this equipment is typically under a manufacturer's warranty. Component or structural breakdown, as well as reduced operating efficiency, will lead the customer back to the manufacturer. It may be difficult for the manufacturer, however, to determine whether the failure is due to equipment flaws or to equipment overload.
To balance the interest in hauling at maximum potential with the interest in maximizing equipment life, equipment owners often request manufacturers to provide an “acceptable” overload amount (or percentage above the target, or acceptable, payload), wherein the adverse effects to the equipment are minimized while still permitting the hauling of large loads.
Currently, systems exist that determine and store the payload weights of a vehicle. One such system is shown in U.S. Pat. No. 5,182,712 entitled “Dynamic Payload Monitor”. This system includes an on-board processor that stores a set of payload weights and may calculate the average payload and overload percentage. While this invention accurately depicts payload and overload information, further calculations may be required to truly appreciate the actual operation of the vehicle. For example, two sets of payload weights may give the same average payload. This average payload will not indicate whether there are some trips with very high weights and some trips with very low weights, versus whether a majority of trips occurred at or near the average weight. Further, the currently available systems do not provide the owner with sufficient information to alter his behavior in order to obtain and/or continue compliance.
The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.